Relations of Manganese and Other Cations 



173 



power in these samples toward hydroquinone, showing that this power 

 varied with the amount of manganese present. He then extracted the 

 so-called laccase from lucern, at the time of flowering, and found the 

 amount of manganese present to be very slight. The samples did not 

 oxidize hydroquinone. When small amounts of manganese were added 

 oxidation took place. Bertrand's results with the lucern extract are as 

 follows : 



Experiment 



Material tested 



O2 absorbed . 



(cubic 

 centimeters) 



1 



Check, manganese alone 



Laccase of lucern 



3 



2 



0.2 



3 



Laccase of lucern plus manganese 



6.3 







When the manganese was replaced by other metals, such as Fe, Al, Sn, 

 Zn, Cu, Mg, and K, the amount of oxygen absorbed was in no case greater 

 than a few tenths of a cubic centimeter. 



Bertrand states further that all manganous salts are capable of oxidizing 

 hydroquinone, pyrogallol, paramidophenol, guaiac, and related com- 

 pounds. His experiments with the action of manganese salts on these 

 compounds lead to the conception of oxidases as special combinations of 

 manganese. In this conception the manganese would be the real active 

 agent, which functions as an activator and a carrier of oxygen. 



Voelcker (1903) observed a deeper green color in the tops of wheat 

 grown in cultures to which small amounts of manganese chlorid were added. 



Trillat (1904) found that the addition of manganese to oxidases results 

 in greater activity of these so-called enzymes. 



Stoklasa (1911) considers manganese and aluminium to be important in 

 photosynthesis, since they collect mainly in the leaves of plants. 



There are numerous reports indicating that manganese may act as a 

 stimulant when applied to soils in small amounts or when present in solu- 

 tion cultures. 



Voelcker (1903) reported that in 1902 the addition of various salts of 

 manganese to pots of soil resulted in some cases in a slight increase in 



